Delivery devices may be used to inject anesthetics into patients. The delivery devices may include a needle for penetration of the tissues of the patient, and a reservoir for storage of the anesthetics. A practitioner may insert the needle into the patient, and then inject the anesthetics from the reservoir into the patient through the needle.
Using some known delivery devices, however, a practitioner may not know whether the needle is in the correct anatomical region of the patient. For example, a practitioner or user of the known delivery devices might not know whether the tip of the needle is disposed within an organ, such as a bladder, a blood vessel, or a tissue.
Accordingly, it is desirable to provide a delivery device that allows the practitioner or user to determine the type of material that the tip of the device is disposed within.